Facts about the animal kingdom

Why Do Dogs Get Stuck When Mating?

Josie F. Turner
By Josie F. Turner, Journalist specialized in Animal Welfare. Updated: January 11, 2024
Why Do Dogs Get Stuck When Mating?

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Dogs get stuck together when mating due to the physiology of their reproductive organs. The reproduction of dogs has adapted over time to best ensure mating is successful. They have various physical and behavioral processes which allow this to happen. This includes the estrous cycle, also known as the heat cycle. During this cycle, females will alert males to their state of fertility and males will compete to mate with her. If successful, they will have sex, a process during which they get stuck together. Although it can look uncomfortable or even painful, it is completely normal.

At AnimalWised, we explain by asking why do dogs get stuck when mating? We explain the reasons for dogs being locked together during sex and what you should or shouldn't do if this happens to your dog.

You may also be interested in: How to Get Dogs Unstuck After Mating
  1. The reproductive system of the male dog
  2. The reproductive system of the female dog
  3. What causes dogs getting stuck together after mating?
  4. Can a neutered dog still lock with a female?
  5. Should I break two dogs stuck together during mating?

The reproductive system of the male dog

In order to understand why dogs get stuck when mating more easily, it is essential to do a brief review of the anatomy of the reproductive system of the male and the female. Thus, the dog's internal and external apparatus consists of the following parts:

  • Scrotum: the scrotal sac is responsible for protecting and maintaining a proper temperature in the dog's testicles. It is also the visible part of the male canine reproductive system.

  • Testicles: located within the scrotum, their function is to produce both sperm and male hormones such as testosterone. They have an ovulate shape, are located in a horizontal position and they tend to be symmetrical.

  • Epididymides: located on both testicles, they are the tubes responsible for storing and transporting sperm to the vas deferens. These tubes are composed of a head, body and tail.

  • Vas deferens: it starts at the tail of the epididymis and has the function of transporting the sperm into the prostate.

  • Prostate: this gland surrounds the neck of the bladder and the beginning of the urethra. Its size varies from breed to breed. Its function is to generate a substance called prostate fluid or seminal plasma for easy transportation of spermatozoa. it also nourishes them.

  • Urethra: this conduit not only transports urine from the dog's bladder, but is also part of the canine reproductive system transporting sperm and prostatic fluid for final ejaculation.

  • Foreskin (prepuce):this is the fold of skin covering the penis to protect and lubricate it. The second function of the foreskin is its ability to produce a liquid called smegma, which is greenish, for this purpose.

  • Penis: in its unaroused state it is in the inside of the foreskin. When the dog feels excited, he begins the erection and, consequently, the appearance of the penis is outwards. It consists of the penile bone, which allows penetration, and the penile bulb, a ventral groove which allows the so called ‘knotting’.

Learn more about the anatomy of a male dog with our related article.

Why Do Dogs Get Stuck When Mating? - The reproductive system of the male dog

The reproductive system of the female dog

As it is the case with the male genitals, the female dog's reproductive system consists of internal and external organs. It is the shape of these organs which lead to dogs getting stuck together after mating. Therefore we will briefly explain the function of each of part:

  • Ovaries: with an oval form, they have a similar function as the testicles in males. They produce ovules and female hormones such as estrogen. As with the male prostate, the size of the ovaries may vary depending on the breed.

  • Oviducts: these tubes in each of the ovaries have the function of moving move the egg to the uterine horn.

  • Uterine Horn: two tubes that carry the eggs to the body of the uterus if they have been fertilized by the sperm.

  • Uterus: it is here where the nidation (implanting of an embryo) of the zygotes takes place to become embryos, fetuses and, subsequently, puppies.

  • Vagina: not to be confused with the vulva, the vagina is the internal organ and the vulva the external. In the dog, it lies between the neck of the uterus and the vaginal vestibule, being the place in which the intercourse takes place.

  • Vaginal vestibule: located between the vagina and the vulva, it allows penetration during mating.

  • Clitoris: as with human females, the function of this organ is to produce pleasure or sexual stimulation to the dog. In turn, this helps to encourage fertilization.

  • Vulva: as we stated above, it is the dog's external sex organ, and is changes size during the mating period.

What causes dogs getting stuck together after mating?

Once penetration has been produced, the male tends to ‘dismount’ the female, but stays attached. The dog will likely turn around to face the opposite direction, but getting stuck means they can't go anywhere. This leads the guardians of both animals to wonder why the dogs have been stuck after mating and how to separate them. This happens because the dog's ejaculation occurs in three phases:

  1. Urethral phase: this takes place during the beginning of the penetration, and therein the dog first ejects a liquid free of sperm. Penetration does not occur due to an engorged penis, but the baculum, also known as the penis bone.

  2. Sperm phase: after the first ejaculation, the animal completes engorgement and starts a second ejaculation, this time with sperm. During this process, there is an increase in penile bulb size due to venous compression of the penis and consequent blood concentration. At this point, the male turns around and dismounts the female, leaving the dogs stuck.

  3. Prostatic phase: while the male has already removed the penis from the female, copulation has not ended, as once the dog has turned away, the so-called ‘knotting’ occurs. This is also known as the copulation tie. The penile bulb remains engorged in the vagina. The expulsion of the third ejaculation has a much lower number of sperm than the last. Once the bulb relaxes and recovers its normal state, the dogs are unstuck.

This way, once the three phases of the ejaculation of the male have been reviewed, we see how the copulation tie gives us the answer to the question why dogs get stuck when mating. The expansion of the penile bulb locks the male into the female. The size it becomes means it cannot pass through the vaginal vestibule, which closes precisely to ensure this fact and avoid damage to the female.

In total, the intercourse can last between 20 to 60 minutes, 30 being the usual average. After the dogs are no longer locked together and become unstuck, you will likely see the male dog lick his still swollen penis and the female dog lick her vagina. This is for hygiene purposes, as well as to relive the sensation of being stuck.

Can a neutered dog still lock with a female?

In humans, sterilization procedures such as a vasectomy still allow for sexual intercourse to occur. However, neutering in dogs is a more invasive process than a vasectomy. It requires castration, i.e. the surgical removal of the dog's testicles.

Castration in dogs makes sexual reproduction impossible. Even if the dog were to mate with a female, there would be no sperm produced to allow for fertilization. Although it is not impossible, it does make sexual intercourse in dogs very difficult.

The testicles of dogs not only produce sperm, but they produce sex hormones which allow them to have intercourse. Once the testicles are removed, the dog produces much less of the sex hormone testosterone. This prevents the animals form achieving full arousal. It also usually kills their sex drive and, therefore, they won't have any interest in sex.

The result is that neutered dogs do not usually still lock with a female because they are much less likely to have sex in the first place. Some neutered dogs will still exhibit sexual behaviors such as trying to mount another dog. This usually happens in dogs which are neutered after they have reached sexual maturity. They are normally carrying out sexual behaviors, but they rarely will try to have full sexual intercourse with another dog.

Why Do Dogs Get Stuck When Mating? - Can a neutered dog still lock with a female?

Should I break two dogs stuck together during mating?

If you have understood the above reason for dogs getting stuck together, you will know trying to break them apart is dangerous. The dog's female and male anatomy do not allow removal of the penis before the end of the dog's third ejaculation. If you separate them forcefully, both animals would be wounded and harmed. Not only would intercourse would not come to its end, but you could serious rupture their sexual organs. The animals need to carry out their natural mating process, allowing them a relaxed and comfortable atmosphere.

It is common to hear the female issue sounds similar to crying. It is possible she will growl and bark. However, even though we may want to spare her any pain, trying to break them apart after getting stuck can cause the dogs even greater pain. It is most advisable not to boost their stress levels and let them separate from each other naturally.

Once the intercourse has ended, if the eggs have been fertilized and the dog becomes pregnant, it will be necessary to provide her with the best level of care. To help provide said care, we recommend the following articles:

If you want to know more about dogs getting stuck together while mating, we have also created this video to help you better understand the process:

If you want to read similar articles to Why Do Dogs Get Stuck When Mating?, we recommend you visit our Facts about the animal kingdom category.

  • Valera, M.A. (n.d.) Canine Reproduction. Centaur veterinary polyclinic: Alcorcón.

  • Gradil, C. M., Yeager, A., & Concannon, P.W. (2006). Assessment of of the canine male reproductive problems. IVIS.

  • Xiomara, L. (2006). Seminal extraction in the dog. Spanish Specialist Veterinary Association of Small Animals, 26(4), 380-381.
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What did you think of this article?
My female dog (7) and my make dog (1) mated but the thing is She s to old to be pregnant so she separated herself from him is that dangerous or?
Administrador AnimalWised
Hi Ava,

If she separated herself, she may have had to use excessive force. This could cause tissue damage, so it may be a good idea to take her to a veterinarian. However, it is also possible they didn't mate to the point they became stuck and, therefore, removed herself without problem. Regardless, you should not keep non-neutered dogs of the opposite sex together as they will likely want to mate with each other.
Jopestkil Kenya pest
Unexplainably complex.
David Stephenson
Listen, this is the easiest thing to fix. The male dogs penis is anchored under the base of his tail. If you place your thumb and first finger either side of the base of his tail, you will feel the blood pulsing into the penis. Just slowly press and pinch your fingers down and firmly together and close off the blood supply. The male dog's penis will deflate and the dogs will immediately separate.
Amazing to know this.
Administrador AnimalWised
Yes Jacqueline,

It's definitely an odd behavior when you come across it and not much less odd when you know what's happening!
That is how they were created and that is their nature
Quite interested what I've just read,have learned something on dogs that would make me curious to always watch them when they matting....
This has finnaly answered my question of why dogs really get stuck together. I've always asked myself in the last but just knowing that the penis gets too big to pass wasn't enough of an answer. Because there's pretty much always a reason in the evolutions of animals and their behaviour.
I would still however, to know if the female dog DOES experience pain during the third ejaculation. As always it seems the female is in a lot of pain.
Also to learn that the female also has a clitoris, does that mean that the female senses pleasure too??
Would love to know the answers to those.
Administrador AnimalWised
Hi Shane,

As with humans, dogs can experience some pain during sex, especially if it is the first time. Yelping is, however, normal and shouldn't cause concern, so it may seem they are in pain when they are not. It is natural and the ‘stuck together’ stage doesn't seem to cause any undue pain unless they are force apart. All mammal species exhibit a clitoris, but research on non-human subjects is relatively scant. We can see that it is possible they do have an orgasm as the contractions can aid insemination. Males masturbate for pleasure, so it is likely females will also sense pleasure to encourage procreation. Further research, however, is needed for conclusive proof. Hope this helps!
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Why Do Dogs Get Stuck When Mating?